Dye developer image transfer systems



United States Patent 0 A DYE DEVELOPER IMAGE TRANSFER SYSTEMS ABSTRACT OF THE DISCLOSURE Increased print densities are produced in dye developer diffusion transfer systems by processing exposed negatives in the presence of dimethylsulfoxide, 2,2-thiodietha- 1101. or a mixture thereof.

This invention relates to the art of photography and more particularly to a multicolor diffusion transfer process in photography and materials adapted to use in the process.

A diffusion transfer color process has been described in a number of patents, including British Patent 804,971, published Nov. 26, 1958, wherein photographic elements containing silver halide emulsion layers and layers containing diffusible dye developers (dyes having a silver halide developing function) are exposed to record the latent image in the silver halide and then treated with an alkaline processing composition which permeates the emulsion layers and layers containing the dye developers which then develop the latent images to silver images. At the same time oxidation products of the dye developers are formed in situ with the silver images and which are relatively nondiffusing in the colloid vehicle of the layers.

The non-diffusing character of the oxidized dye developers is apparently due at least in part to a decrease in solubility in the alkaline processing liquid, and may also be due to a hardening effect of the oxidized developer upon the colloid vehicles of the layers which retards the diffusion of the oxidized dye developers. The residual unoxidized dye developers remaining in the layers in imagewise distribution are transferred by diffusion to a superposed reception element substantially to the exclusion of the silver image and oxidized dye developer to provide a positive dye image.

When an element containing differentially sensitized silver halide emulsion layers is used and substractively colored dye developers are present in or contiguous to the respective emulsion layers, upon treatment with the processing liquid the dye developers are oxidized and rendered non-diffusing in the developed regions of the layers and the residual dye developer images in the positive regions are transferred by diffusion and in register to the reception element to provide a multicolor reproduction.

As is apparent, the success of the process depends in part upon the extent to which the dye developers in the exposed (negative) regions of the emulsion layers have been rendered substantially non-diffusing in the development reaction. Thus, if a quantity of unoxidized dye developer remains in a fully exposed negative region corresponding to the highlights of the subject, it will be transferred to the reception layer along with the unreacted dye developer in the positive regions and appears as high minimum density on the resultant color print. Typical 3,431,107 Patented Mar. 4, 1969 dye developers such as 1,4-bis[ii-(2,5-dihydroxyphenyl)- ethylamino]-anthroquinone NHOHzCHPQ are relatively weak silver halide developing agents even when used at the comparatively high pH of the order of 13 required in the process and do not so rapidly develop sensitometric properties of the emulsions as to obtain dye images having a full scale of density and contrast expected with other developing agents. As a result, color prints obtained in the processes may exhibit an undesirable high minimum density in the highlight regions, low color saturation, contrast and density and the color separation is poor.

It is therefore an object of this invention to provide improved photographic products that are suitable for the production of dye developer images of increased density.

A further object is to provide a process for the production of dye developer images having higher maximum densities.

These and other objects are achieved in accordance with the present invention whereby multicolor transfer processes using dye developers are conducted in contiguity with a sulfur-containing organic compound selected from the group consisting of dimethylsulfoxide, 2,2-thiodiethanol, and mixtures thereof.

It has been found that greatly increased image densities are obtained by processing an exposed photographic element comprising a support having superposed thereon a plurality of light-sensitive silver halide emulsion layers which are optically sensitized to different regions of the spectrum, and a dye developer, which is both a silver halide developing agent and a dye, contiguous to the silver halide emulsion layers with an alkaline liquid in the presence of dimethylsulfoxide, 2,2'-thiodiethanol, or mixtures thereof. The latent images are developed in regions of exposure of the silver halide emulsion layers thereby immobilizing the dye developers in these regions of exposure, while the dye developers in the undeveloped regions diffuse imagewise in register to a dye developer reception element to yield a multicolor dye developer image thereon of improved density.

In a typical process the sensitive element contains superposed gelatin emulsion layers sensitized to the red, green and blue regions of the spectrum. Under each emulsion layer is a light-sensitive gelatin layer containing a subtractively colored dye developer (cyan, magenta or yellow colored dye developer). Gelatin interlayers separate the middle emulsion layer and its underlying layer of dye developer from the other two emulsion layers and dye developer layers.

The sulfur-containing compounds may be suitably provided directly in the alkaline processing composition along with a thickening agent, such as a hydroxyethyl cel- 3 lulose, in the dye developer reception element or in the light-sensitive element containing the dye developers. However, the sulfur-containing compounds of the present invention are preferably provided in the viscous alkaline processing solutions.

According to a preferred embodiment, a reception element containing a support and a reception layer is positioned so as to receive dye images transferring by diffusion from the sensitive element, with a rupturable container of a viscous alkaline processing solution therebetween. Upon rupture of the container as by means of passing the assembly between rollers in a camera so as to distribute the contents uniformly across a predetermined area of the sensitive element, the solution penetrates the emulsion layers with the result that the latent image in the silver halide is developed to silver and the dye developers in the areas including the regions of development each become immobilized and rendered non-diffusing. The unreacted dye developers of the layers diffuse imagewise in register to the reception layer and form dye images thereon.

The optimum concentration of the sulfur compounds in the processing solution may vary. The factors having an effect on the choice of a suitable concentration include: the composition of the photosensitive element; transfer time; temperature; and the amount of processing solution provided between the photosensitive element and the dye developer reception element. Although the present sulfur compounds will increase the print densities, the degree of improvement will vary. For example, concentrations of between about 1.0 and about 15.0 percent dimethylsulfoxide by volume of the processing solution will generally increase the transferred density of yellow and magenta dyes to a greater extent than that of the cyan dyes. A preferred concentration range for the sulfurcontaining organic compound is, for example, between about 1.0 and about 6.0 percent by volume.

The proessing solution used to initiate development of the exposed sensitive elements containing the dye developers should be strongly alkaline in order to accelerate the development activity of the dye developer as much as possible. Alkali metal hydroxides such as sodium hydroxide or alkaline salts such as sodium carbonate are advantageously used in the activator composition for this purpose. However, quaternary ammonium hydroxides or volatile amines such as diethyl amine, which have the advantage of being volatized from the prints and therefore leave no residue of alkali thereon which might tend to decompose the dye images, may also be used.

The sensitive elements of the invention are, of course, adapted to use in a camera for taking pictures in the usual manner. Moreover, the development of the sensitive elements, i.e., the treatment with an alkaline activator solution to initiate development, can also be carried out in the camera by use of rupturable containers of processing solution or other means may be used to spread the processing solution uniformly across the picture area of one or more consecutively exposed images and in contact with the reception layer. For this purpose, it is desirable to use a processing solution containing in addition to strong alkali a thickening agent such as carboxymethyl cellulose or high-viscosity hydroxyethyl cellulose in suitable quantity to obtain the desired viscosity. Other means can be used such as spraying, dipping, roller coating, etc. to apply the processing solution to the exposed element and to initiate its development.

The dye developers which are used in the emulsion layers or in layers adjacent to the emulsion layers are compounds which are both a silver halide developing agent and a dye. They are characterized by being relatively non-dilfusible in the solid colloid layers at a neutral pH but dilfusible in the layers in the presence of the alkaline processing solutions. For the most part the dye developers are insoluble in Water per se, which property usually necessitates the use of organic solvents to incorporate the dye developers into the organic colloid layers of the sensitive elements. Otherwise, the solubility of the dye developers is not particularly important and so long as the dye developers are capable of being immobilized in the layers in the presence of the alkaline processing solution and they are transferable to the reception element, they are useful in the process of the invention.

The dye developers are particularly characterized by containing both a chromophore moiety and at least one moiety such as -a hydroquinonyl radical having a silver halide developing agent function and which radical imparts silver halide development activity to the dye developer molecule as a whole with the result that during development of a silver halide image, the dye developers are oxidized to less ditfusible compounds in the region of exposure and development and the residual dye developers in the undeveloped regions are transported imagewise to mordanted reception layers to provide a dye image thereon. The dye developers of course should not have a desensitizing action toward silver halide emul- SlOIlS.

Representative dye developers of use in the sensitive elements of the invention have the general formula in which M is an aromatic or heterocyclic ring or ring system such as a benzene, naphthalene, tetralin, anthracene, anthraquinone, pyrazole, quinoline, etc., ring and may also be substituted, as by hydroxyl amino, keto, nitro, alkoxy, aryloxy, acyl, alkylamido, arylamido, alkyl, aryl, carboxamido, sulfonamido, carboxyl or sulfo groups. D represents a silver halide developing agent moiety imparting the developing agent function to the dye developer such as a hydroquinolyl group which may be substituted wtih amino, alkylamino, alkyl, hydroxyl, alkoxyl or halogen groups.

A very useful type of dye developers disclosed in Australian Patent 220,279, accepted Dec. 17, 1958, and German Patent 1,036,640, Aug. 14, 1958, have the general formula.

wherein P=1 or 2; R=an alkylene group of from 1 to 5 carbon atoms; Ar=an aryl group of the benzene or naphthalene series; each Z=a lower alkyl group such as methyl or ethyl, or halogen e.g. chlorine; Z=a lower alkoxyl group such as methoxy or ethoxy, halogen or lower alkyl group; m=0, 1 or 2; Y=a 2,5- or 2,3- or 3,4- dihydroxyphenyl group which may be substituted by alkyl or halogen groups; Q=the residue of a coupling component such as a phenol, naphthol, 5-pyrazolone or open chain reaction methylene coupler containing the group COCH CO, for example:

4-[p-(2,5'-dihydroxyphenyl)-phenylazo]-5-acetamidol-naphthol 4- [p-(2,5'-dihydroxyphenethyl)-phenylazo]-5-benzamidol-naphthol 1-phenyl-3-methyl-4-[p-(2,5'-dihydroxyphenethyl)-phenylazo]-5-pyrazolone 2-[p-(2',5-dihydroxyphenethyl)-phenylazo]-4-acetamidel-naphthol 2- [p-(2',5'-dihydroxyphenethyl)-phenylazo]-4-amino-1 naphthol on 0-CHr-CHz-N=N I OH 1-phenyl-3 -N-n-butyl-carboxamido-4- [p-(2,5 '-dihydroxyphenethyl) -phenylazo -5 -pyrazo10ne.

1-phenyl-3-N-n-hexylcarboxamido-4- [p- (2,5'-dihydroxyphenethyl )-phenylazo] -5 -pyrazolone.

1-phenyl-3-carbethoxy-4- [p- 2,5 '-dihydroxyphenethyl phenylazo1-5-pyrazolone.

2- p- (2,5-dihydroxyphenethyl -pheny1azo] -4-isopropoxyl-naphthol.

1-phenyl-3-N-cyclohexylcarboxamidol- [p-( 2,5 -dihydroxyphenethyl -phenylazo] -5 -pyrazolone.

l-phenyl-3 -phenyl-4- [p- 2,5 -dihydroxyphenethyl -phenylazo -5-pyrazolone.

2- 4'- [p- (2",5 "-dihydroxyphenethyl phenylazo] -a-naphthylazo -4-methoxyl-naphthol.

1-phenyl-3 -amino-4-(4- [p-(2",5 "-dihydroxyphenethyD- phenylazo] -2,5 -diethoxypheny1azo -5-pyrazolone.

1-acetoXy-2- [p- B-hydroquinonylethyl -pheny1azo -4- methoxy naphthalene.

4-isobutoxy-2- [p-( fi-hydroquinonylethyl -phenylazo -1- naphthol.

l-acetoxy-Z- [p- (fl-hydroquinonylethyl) -phenylazo] -4- propoxy naphthalene.

2- [p- (2,5'-dihydroxy-4'-methylphenethyl) phenylazo] -4- propoxy-l-naphthol.

1-phenyl-3- [N- fi-ethylhexy -carb oxamido] -4- [p- (,8'-hydroquinonylethyl -phenylazo] -5 -pyrazolone.

1-phenyl-3- N-n-heptyl) carboxamido-4- [p-(B-hydroquinonylethyl) -phenylazo] -5-pyrazolone.

1- o-carboxyphenyl) -3 -phenyl-4- [p- 2,5 -trifluro acetoxyfi-phenylethyl phenylazo] -5-hydroxy pyrazole lactone.

1- o-carboxyphenyl -3 -N-phenylcarboXamido-4- [p- (B'- hydroquinonylethyl -phenylazo] -5-hydroxypyrazole lactone.

Another class of dye developers disclosed by British Patent 804,971, Nov. 26, 1958, and British Patent 804,- 973, Nov. 26, 1958, have the general formula wherein A represents an anthraquinone nucleus, D represents an organic radical having a developing function and containing an aryl nucleus such as benzene or naphthalene nuclei, substituted by at least two substituents selected from hydroxyl, amino and substituted amino groups so that the resulting compound is capable of developing exposed silver halide, Q represents a hydrogen atom or an alkyl group or, when the substituents on the aryl nucleus of D are hydroxyl groups, Q may also be an acyl group, which may be aliphatic, e.g., acetyl or aro-' matic, e.g. benzoyl, Z is a bivalent organic radical containing at least one methylene (CH group, m is a positive integer less than 5 and each Y may be a hydrogen or halogen atom or an amino, alkyl, aryl, nitro, alkylamino, arylamino, aryloxy, alkoxy, hydroxyl, sulphonami do, carboxy, sulpho,

t a -ND or --N-ZD group.

Examples of these dye developers are:

1,4-bis-(2,5'-dihydroxyanilino)-anthraquinone,

1,5 -bis-( 2',5 -dihydroxyanilino)-4,8-dihydroxy-anthraquinone,

1,4-bis[,3-(3 ',4'-dihydroxyphenyl) ethylamino]-anthraquinone,

(cyan dye developer) 1,4-bis [B- (2',5'-dihydroxyphenyl) -isopropylamino] -anthraquinone,

1,4-bis [fi- (2',5'-dihydroxyphenyl -ethylamino] -anthraquinone,

l-chloro-4- [B- 2,5-dihydroxyphenyl) -ethylamino] -anthraquinone,

N-monobenzoyll ,4-bis- [,B- 3,4'-dihydroxyphenyl) -ethylamino] -anthraquinone,

N-monobenzoyl-1,4-bis[,3-(2,5'-dihydroxyphenyl) -ethylamino] -anthraquinone,

5 ,8-dihydroxy- 1 ,4-bis fi- (hydroquinonyl-a-methyl) -ethylamino] -anthraquinone,

1,4-bis B- (hydroquinonyl-a-ethyl ethylamino] -anthraquinone,

5-hydroxy-l,4-bis 6- (hydroquinonyl-ot-methyl) -ethylamino] -anthraquinone,

1- fi-hydroxy-a-ethyl-ethylamino) -4- (fl-hydroquinonyl-amethyl)-ethylamino-anthraquinone, and

1- butanol-2-amino -5,8-dihydroxy-4-hydroquinonylisopropylamino-anthraquinone.

Acylation of amino-nitrogen atoms which are part of the chromophoric system has the elfect of shifting the visible absorption band of the compound toward higher frequencies (shorter wavelengths). Thus, acylating one amino-nitrogen of the cyan, 1,4-bis-[fl-(2',5'-dihydroxyphenyl)-ethylamino]-anthraquinone changes its color to a magenta, and acylating both the amino-nitrogen atoms changes its color to an orange-yellow. Similarly the acylation of hydroxyl groups of the above types of dye developers can be expected to shift the color of the dye developers. Thus, the dye developers may undergo a change in structure and/or color during the development reaction, for example through hydrolysis, and the dye which is transferred may have a color different than that of the dye developer originally present in the sensitive element.

Additional dye developers are disclosed in Belgian Patent 554,935, British Patents 804,971, 804,973- and French Patent No. 1,168,292.

The following dye developers are also useful in the sensitive elements and processes of the invention:

Cyanurated dye developers such as Z-hydroquinoneamino-4-(p-phenylazo)anilino-6-hydroxy-4-triazine (Canadian Patent No. 579,038).

Anthraquinone dye developers such as 1,4-bis-(2,5- dihydroxyanilino)-anthraquinone and 1,4-diamino-N-(fi- 2, -dihydroxyphenyl-a-methyl-ethyl) 2,3 anthraquinone-dicarboximide.

Amino substituted anthraquinone dye developers such as prepared by reaction of 1-amino-4-(p-aminoanilino)- anthraquinone-Z-sodium sulfonate with chloroacetamido hydroquinone monobenzoate.

Dye developers obtained by reaction of l-phenyl-3- amino-4-phenylazo-5-pyrazolone or l,4-bis(fi-aminoethylamino)-anthraquinone with homogentisic acid lactone or acid chloride, or gentisic acid chloride e.g. l-phenyl-3- (2',5-dihydroxyphenyl-acetamido) 4 phenylazo 5 pyrazolone (Blout et al. Canadian Patent 577,021, dated June 2, 1959).

Naphthamide dye developer such as l-(2,5-dimethoxyphenylazo)-2-hydroxy N-(2,5'-dihydroxyphenyl) 3 naphthamide (French Patent 1,168,292, dated Aug. 25, 1958).

Diazo dye developers such as 2-[p-(1-hydroxy-3,6- disulfo 8 amino 2 naphthylazo) 3,3 dirnethoxybisphenyleneazo]-hydroquinone and 2-(2',5'-dimethoxy- 4-[p-(2,5" dihydroxyphenethyl)phenylazo] phenylazo)-l,8-naphthalene cliol-3,6-disulfonic acid.

Arylazonaphthol dye developers, e.g. l-amino-4-phenylazo-Z-naphthol.

Anthrapyridone dye developers e.g. 1-acetyl-3-B-(2,5'- dihydroxyphenyl) ethyl-6 fi-(2,5-dihydroxyphenyl) ethylamino-anthrapyridone.

Thiohydroquinone dye developers, e.g. l-phenyl-3- methyl 4 [p (2,5' dihydroxyphenylthioethyl) phenylazo]-5-pyrazolone (Belgian Patent 568,344).

Ortho coupled dye developers exhibiting limited sensitivity to chanms of pH e.g. 2-(p-[2",5"-dihydroxyphenoxy1phenylazo)-4-methoxy-1-naphthol and 1-phenyl-3- methyl 4 [p (hydroquinolylsulfonyl) phenylazo]-5- pyrazolon Oxalyl ester dye developers, e.g. 1-phenyl-3-arnino-4- [p-(2',5' bis ethoxalyloxyphenethyl) phenylazo] 5- pyrazolone.

V'uco compounds may be used similarly e.g. l-phenyl- 1' a methyl 4 (2' methyl 4' diethylamino)anilino -5- pyrazolone, which do not exert a filtering action on underlying emulsion layers and which are immobilized in the developed regions, diffuse imagewise from undeveloped areas to the reception layer and are oxidized to colored images therein.

The dye developers may be incorporated into the emulsion layers or into the layers thereunder by several methods. For example, the dye developers may be dissolved in organic solvents and precipitated into gelatin solution or the dye developers may be ball-milled in gelatin solutions to reduce their particle size. However, particularly favorable results are obtained when a hydroquinone derivative (hereinafter described) is present in one or more of the layers of the sensitive element and the dye developers have been incorporated into the gelatin layers under the emulsion layers by dissolving the dye developers in high boiling solvents such as ditetrahydrofurfuryl adipate or 2-(2-butoxyethoxy)ethyl acetate and milling the mixture in gelatin solution in a colloid mill.

When high boiling solvents having low solvent activity for the dye developers, such as dibutyl phthalate, are used it is desirable to dissolve the dye developer in a mixture of the high boiling solvent and a low boiling solvent such as cyclohexanone, methanol, etc., which evaporates readily from the coatings during the subsequent drying operation.

Many of the dye developers can be used with the high boiling solvents (in absence of low boiling solvents) such as the following:

Ditetrahydrofurfuryl phthalate fl-Methoxyethyl phthalate Ethyl N,N-di-n-butylcarbamate Guaiacol acetate (o-methoxyphenyl acetate) Tetrahydrofurfuryl propionate Triethyl citrate Acetyl triethyl citrate Tricresyl phosphate Tri-p-tert. butylphenyl phosphate Triethylphosphate Tri-n-butylphosphate Triphenylphosphate Isoamyl acetate Ditetrahydrofurfuryl succinate Methyl acetate Ditetrahydrofurfuryl adipate Tetrahydrofurfuryl benzoate N-n-amylphthalimide Ethyl N,N-di-n-butylcarbamate Diethyl lauramide Dibuthyl lauramide Lauroyl piperidine N-n-butyl acetanilide Tetraethyl phthalamide N-n-amyl succinimide 4-methyl-2-pentano1 2,4-di-n-amylphenol Ethylene glycol monobenzyl ether Methyl isobutyl carbinol Furfuryl alcohol Cyclohexanone 2-(2-butoxyethoxy)ethyl acetate The isomeric 2-, 3- and 4-methylcyclohexanones are particularly useful lower-boiling solvents for use with the above high-boiling solvents for dispersion of dye developers such as the cyan dye developers 1,4-bis-(2,5-dihydroXyphenyl-isopropylamino) anthraquinone, 5,8-bis [fl-(hydroquinoyl-a-methyl)-ethylamino] quinizarin and 1, 4-bis-(2,5-dihydroxyphenylisopropylamino) 5 hydroxyanthraquinone, and the magenta dye developer 4-methoxy- 2-[p-(,B-hydroquinoylethyl)-pheny1azo]-l-naphthol. As a result the gelatin solutions containing dispersions of dye developers produce stable dried coatings in which the dye developers do not tend to crystallize out.

The dye developers are employed in the sensitive elements contiguous to the silver halide of the emulsion layers, that is, they may be present in one or more of the emulsion layers or preferably in a hydrophilic organic colloid layer immediately next to and particularly under the silver halide emulsion layer. Especially good results are obtained when the dye developers are positioned so as to be present in the layer immediately under the emulsion layer, the sensitivity of which is complementary to the color of the dye developer. It appears less desirable to locate the dye developer in a layer positioned above the corresponding layer of silver halide emulsion. The contiguity of the dye developer with respect to the silver halide can take the form of a mixed packet system wherein the dye developer may be present in a matrix surrounding a particle or globule containing silver halide grains.

In multilayer sensitive elements the order of arrangement of the dilferentially sensitized silver halide emulsion layers on the support can be such that the red sensitive layer is on the support, the blue sensitive layer outermost and the green sensitive layer in between. Suitable nondiffusible filter dyes, w ich may be color-formers, can be incorporated between the light-sensitive layers. For example, a yellow dye, such as Coupler B of Beavers US. Patent 2,983,608 issued May 9, 1961, can be incorporated in an interlay between the blue and green sensitive emulsion layers, and a magneta colored dye or color former can be incorporated between the green and red sensitive layers. Filter dyes which are color formers can be incorporated in the layer in any convenient manner, such as by one of the processes described in U.S. Patents 2,304,939; 2,322,027; 2,801,170; 2,801,171; and 2,949,360. The dyes can be mordanted, for example with a mordant of the type described in Minsk U.S. Patent 2,882,156. The arrangement can be reversed so as to have the blue sensitive emulsion layer on the support and the red sensitive emulsion layer outermost. In such arrangements of layers the sensitives of the silver halide emulsions should be adjusted so as to prevent recording unwanted blue light images in the emulsion primarily sensitive to the red and green regions of the spectrum, e.g., a silver bromide emulsion can be used for the blue sensitive emulsion and silver chloride emulsions for the other layers. In in stances of this type it may be desirable to utilize the leuco compounds mentioned above in place of one or more of the dye developers which, since they may have some blue absorption, might tend to exert an undue filtering action on the blue sensitive bottom layer.

The hydophilic organic colloid vehicle of the emulsion layers, overcoating layers, of the dye developer layers and of interlayers can be varied somewhat, for example, gelatin, gelatin derivatives such as dibasic acid esters of gelatin, polyvinyl alcohol and cellulose acetate hydrogen phthalate, or mixtures of the hydrophilic organic colloid vehicles, may be used. However, the best and most consistent results, and consequently prints of the highest quality, are obtained when gelatin is used as a colloid vehicle throughout all layers of the sensitive element. In fact, when gelatin interlayers are used they should be at least about 75% of the measured thickness of the yellow dye developer layer and contain at least about two times the amount of gelatin present in that layer in order to prevent undue wandering of the dye developer and development products from layer to layer.

Other hydrophilic organic colloids yield less desirable results when used in the layers. For example, when some of the layers contain gelatin vehicle and interlayers of polyvinyl alcohol or cellulose acetate hydrogen phthalate are used, the layers tend to strip apart particularly when dry. Also, when gelatin is used throughout more uniform transfer of the alkaline processing solution and hydroquinone derivative through the layers is obtained and the dye developers comprising the final print transfer more readily to the reception layer.

It is also contemplatedto employ an onium compound, such as a heterocyclic quaternary ammonium compound capable of forming methylene bases soluble in alkaline solution, especially in the presence of a substantially colorless hydroquinone derivative, preferably in contiguity with the silver halide emulsions, dye developers and sulfur compounds of this invention. The use of onium compounds which are diffusible in alkaline solution through organic layers of the sensitive elements, especially in the presence of the hydroquinone derivative, will increase the transfer of the dye developers from unexposed areas of the negative, while inhibiting the transfer of oxidized dye developers from the exposed areas and thus improve the highlights.

Useful results are obtained through the use of quaternary ammonium compounds. As is known, quaternary ammonium compounds are organic compounds containing a pentavalent nitrogen atom. Generally, they can be considered as derivatives of ammonium compounds wherein the four valences usually occupied by the hydrogen atoms are occupied by organic radicals. Generally, the organic radicals are joined directly to the pentavalent nitrogen through a single or double carbon-to-nitrogen bond. The term quaternary ammonium, as used herein, is intended to cover compounds wherein the pentavalent nitrogen is one of the nuclear atoms in a heterocyclic ring as well as those wherein each of the four valances is attached to separate organic radicals, e.g., tetraalkyl quaternary ammonium compounds.

Particularly eflicacious quaternary ammonium compounds which form methylene bases diflfusi ble in alkaline solution are heterocyclic in nature, and have the general formula wherein D represents the non-metallic atoms necessary to complete the heterocyclic nucleus of the quaternary ammonium compound containing 1 or more of the reactive methyl groups CH R in one or more of the nuclear positions, the other nuclear positions being substituted or not, such as quaternary salts of the pyridine, quinoline, benzoquinoline, benzoxazole, benzoselenazole, thiazole, benzothiazole, naphthothiazole, benzimidazole, isoquinoline series, etc., n is 0 or 1, R is an alkyl group, an aryl or aralkyl group of the benzene series, or substituted alkyl, aryl or aralkyl groups of the benzene series, the alkyl chains preferably being lower alkyl of from 1 to 4 carbon atoms, R is a hydrogen atom or one of the groups represented by R, and X represents OH or an acid anion such as Br, CH SO or The onium compounds can be used in varying amounts depending upon the particular compound. When used in the alkaline processing solution, useful results can be obtained with from about 0.2 to 15% of onium compound. In some cases about 0.2 to 3% is best. Similarly, the amount used in the sensitive element and receiving sheet will vary with the onium compound selected.

The quaternary ammonium compounds comprising a preferred group are pyridinium salts which form the dilfusible methylene bases and which have the above formula, the pyridinium nucleus being substituted with from 1 to 3 active methyl groups -CH R present in at least one of the 2, 4 or 6 positions, e.g., a lower alkyl group such as methyl, ethyl, propyl or substituted lower alkyl groups such as hydroxyalkyl, e.g., hydroxyethyl, which alkyl groups act as methylene base precursors. Positions 3 and 5 may or may not be substituted with, e.g., halogen, lower alkyl and haloalkyl groups such as chlorine, methyl, ethl, propyl or chloroethyl groups.

Typical salts having the above formula are as follows: l-bcnzyl-Z-picolinium bromide I CHzC H Additional onium salts which are useful in the process of the present invention are fully described in U.S. Patent No. 3,161,506.

The hydroquinones which have the requisite properties are substantially colorless, substantially Water-insoluble, and soluble and dilfusible in alkaline solution through organic colloid layers such as gelatin and are exemplified by the following:

Phenylhydroquinone 2-hydroxyphenylhydroquinone Phenoxyhydroquinone 4-methylphenylhydroquinone 1,4-dihydroxynaphthalene 2-(4-aminophenethyl)-5-bromohydroquinone 2-(4-aminophenethyl)-5-methylhydroquinone 4'-aminophenethylhydroquinone 2,5-dimethoxyhydroquinone 2,5-dibutoxyhydroquinone m-Xylohydroquinone Bromohydroquinone 3,6-dichlorohydroquinone Z-dimethylaminomethyltoluhydroquinone 2-cyclohexylhydroquinone Sec. butylhydroquinone 2,5-dichlorohydroquinone 2,S-diisopropylhydroquinone 2,5-diiodohydroquinone 3-chlorotoluhydroquinone Tetrachlorohydroquinone 2,5-diphenylhydroquinone 2,S-diresorcylhydroquinone 2,5-dioctylhydroquinone Dodecylhydroquinone The useful hydroquinone derivatives are particularly distinguished from the dye developers containing hydroquinonyl moieties in being substantially colorless and therefore do not impart any color to the print.

The processes of the invention are thus carried out with the silver halide emulsions and dye developers preferably in contiguity with both the quaternary ammonium salts and the hydroquinone derivatives. That is, the quaternary salt may be present in either or both the alkaline processing fluid, the reception sheet, less desirably in the sensitive element, and the hydroquinone derivative in any of the layers of sensitive element such as an overcoating layer, emulsion layer, dye developer layer, and interlayer, or in the reception sheet. Thus, the reception sheet or reception layer may be composed of a mordant for the dye developers such as mentioned below, e.g., poly-4-vinylpyridine and in addition may contain at least one of the hydroquinone derivatives above.

Similarly, the reception layer or sheet may contain the combination of a mordant for the dye developers, at least one of the hydroquinone derivatives and at least one of the onium compounds mentioned, particularly the heterocyclic quaternary ammonium compounds forming the methylene bases.

For some purposes the hydroquinone derivatives may be present in the processing fluid containing the hydroxyethyl cellulose. However, in the present invention use in the fluid is much less desirable since the hydroquinone derivatives are unstable in such solutions and readily undergo oxidation accompanied by discoloration of the prints, unless prepared and stored in absence of air or other precautions are taken to prevent oxidation.

The hydroquinone derivatives used as described, are preferably incorporated into emulsion layers, overcoating, interlayers or other layers, as dispersions in the hydrophilic organic colloid vehicle of the layer. The hydroquinone derivatives may be dissolved in alkaline solution and precipitated into aqueous gelatin solutions by raising the acidity of the solution. However, this is a less desirable procedure because of the instability of the compounds in alkaline solution.

The hydroquinone derivatives may be dissolved in a solvent, such as a lower alcohol, and precipitated into aqueous gelatin solutions for coating on the sensitive element. They may be added to gelatin solutions which are ball-milled to reduce the crystal size. However, the hydroquinones are preferably dissolved in a low molecular weight water-insoluble organic crystalloidal solvent permeable to the alkaline processing solutions and having a boiling point above about 175 C. such as dibutyl phthalate and added to an aqueous gelatin solution which is passed through a colloid mill until the desired degree of subdivision has been attained.

An auxiliary organic solvent can also be used such as one having a solubility in water greater than that of the crystalloidal solvent, of the order of at least about 2 parts per parts of water. Thus the auxiliary organic solvent can be washed from a chilled gelatin dispersion in the presence of the other solvent. The auxiliary solvent may be one having a boiling point at least about 25 C. lower than the crystalloidal solvent in order that it can be removed by volatilization during the drying of a coating to leave the hydroquinone derivative dispersed in only the crystalloidal solvent. As a result, the hydroquinone derivatives are quickly and uniformly dissolved by the alkaline processing composition and transported throughout the sensitive element to produce more uniform development than when the hydroquinone derivatives are incorporated into the element by other means.

The hydroquinone derivatives may be used in one or more layers of the sensitive element in quantities of the order of from about 10 to 100 mgs. or more per square foot. However, the quantity used depends in part upon the amount of silver halide, the layer in which it is contained, the amount of dye developers and the amount of pyridinium salt in the sensitive element or processing solution of reception element. In some instances it may be desirable to form a complex of the hydroquinone derivatives by reaction with sulfur dioxide in a well known manner and to incorporate the complex in the overcoating layer, outer emulsion or other layer of the sensitive element. These hydroquinone-sulfur dioxide complexes tend to be more stable than the hydroquinone derivatives themselves.

As previously mentioned, any suitable means may be employed to apply the processing solution to the exposed element and to effect its development. Thus, several consecutive exposures on a strip of the sensitive element can all be wetted with the alkaline processing solution and the dye developer images transferred to a single strip of reception material to provide several color prints in a single transfer operation.

One method for obtaining the color prints from a strip of the sensitive element containing a series of, for example, three or four consecutive exposures, is to apply the viscous processing solution from a releasably confining or rupturable container in a compartment such as a magazine, integral with a camera in the manner described below, to cause each of the exposed areas to be wetted with the processing composition at approximately the same time in contact with a strip of reception material and the corresponding multicolor images to transfer thereto to provide a series of colored images on a single strip of the reception material.

A different means for providing prints from the sensitive element containing a series of image exposures such as three or four consecutive exposures, is to expose the element to several subjects in a conventional camera not necessarily adapted to use of rupturable containers of the processing composition, and withdrawing the exposed element from the camera in a convenient manner so as to prevent fogging of the emulsions. Thus, the element can be exposed and wound upon itself on a spool in an ordinary roll-film type of camera so as to exclude light, by use of a light-impervious covering such as black paper, a cassette or a magazine.

The element can then be withdrawn from the camera and placed in a convenient portable light-impervious enclosure of small dimension for application of the viscous processing fluid to the element from, for example, a single rupturable container or several rupturable containers corresponding to the number of exposures recorded on the strip of sensitive element or by application of the fluid to the elmeent by means of a wick, roller or similar applicator, so that each of the exposed areas is wetted. As a result the element comprising several image exposures on a single strip of differentially light-sensitive emulsion layers and subtractively colored dye developers contiguous to the silver halide of each emulsion layer, is wetted with the alkaline fluid in the presence of the onion salts. Preferably this is conducted in the presence of the hydroquinone derivatives, and brought into contact with the reception layer for a time sufiicient for adequate development of each image, to cause the silver halide in the several exposed areas of each emulsion layer to develop. The corresponding dye developers are rendered immobile and the dye developers in the unexposed portions of each of the several exposed areas transfer to the reception layer and provide a series of prints thereon composed of the dye developers.

Camera apparatus of the type useful for exposing and processing the sensitive elements of the invention have been described, for example, in U.S. Patent 2,435,717. Such cameras permit successive exposure of individual frames of the photosensitive element from the emulsion side as well as processing of an exposed frame by bringing the exposed portion of the photosensitive elements in superposed relation with a portion of the print receiving element while drawing these portions of the film assembly between a pair of pressure rollers which rupture the container associated therewith and spread the processing liquid between and in contact with the photosensitive element and the corresponding registered area of the print receiving element.

The photosensitive element and print receiving element become formed into a combination wherein the photosensitive element and print receiving element are so superposed with respect to each other that the spread liquid has access to both of the elements. This superposed relationship between the photosensitive and print receiving elements is maintained until the elements are stripped apart following the deposit on the print receiving element of the dye forming the final color image.

The reception layers to which the dye developers are transferred imagewise to obtain the multicolor images may be composed of various materials such as linear polyamides, proteins such as gelatin, polyvinyl pyrrolidone, poly-4-vinyl pyridine, polyvinyl alcohol, polyvinyl salicylal and methyl cellulose. These reception layers are coated on a suitable support such as a paper support, a polyethylene coated paper support, a transparent film or a white pigmented cellulose ester support to obtain a print or pigmented cellulose ester support to obtain a print or transparency as the case may be. Low-viscosity solutions of water-soluble polymers (e.g., hydroxyethyl cellulose) or gums (e.g., gum arabic) containing developer can be coated over the mordant-containing receiving sheet. Such receivers are relatively dry when separated from the sensitive element after processing.

In the process of the invention it may be desirable to employ an antifoggant in the sensitive element, in the alkaline processing solution or the reception element or in each, and a development arresting compound in the reception element. When development arresting compounds are present in the reception element rather than in the sensitive element or solution they do not become become effective until dissolved by the processing solution and have migrated to the sensitive element under development. As a result, the latent image is allowed to develop very rapidly and the development arresting effect is delayed until the development of the exposed areas has essentially reached completion before development is appreciably arrested. This results in the prevention of development in the unexposed areas and increases the amount of dye developer transferreing.

Additional improvement is obtained when the development arrestor is present in the reception layer and the mentioned quaternary salts are present in either the processing solution or the reception layer, or both. Suitable development arrestors are heterocyclic mercaptans such as mercaptotetrazoles and mercaptobenzothiazoles, e.g., 1-phenyl-5-mercaptotetrazole, 2- mercaptobenzothiazole, etc. Many compounds usually considered to be anti-foggants for silver halide do not arrest development as desired.

In a further variation of the invention a small amount of a silver halide solvent such as alkali metal or ammonium thiosulfate or thiocyanate may be incorporated into the alkaline processing composition or the receiving layer, or both, with the result that the effective photographic speed of the process is increased. However, the effect of the silver halide solvent becomes most apparent when either or both the mentioned hydroquinones and quaternary salts are present. Ordinarily the amount of silver halide solvent used is not sufiicient to cause any appreciable amount of silver halide to be dissolved from the unexposed and undeveloped areas of the sensitive element and to be transferred to the reception layer.

Processing these elements, or elements of the type described in Barr et a1. U.S. Patent 3,227,551 issued Jan. 4, 1966, in the presence of urea, an aromatic sulfonic acid such as naphthalene 1,5-disulfonic acid and aromatic carboxylic acids, or salicyclic acid increases the color transfer process, and improves color density of the print obtained. These additives can be incorporated in the processing solution, the receiver or the light sensitive element.

The invention contemplates sensitive elements wherein the emulsion layers, contiguous hydroquinone derivatives and dye developer layers are integral with the support, e.g., coated on a support capable of receiving the dye developer images, the support being of a nature such that it can be stripped away from the sensitive layers or a stripping layer may be provided between the reception layer and the other layers to facilitate the stripping operation. The viscous alkaline fluid can thus be supplied as described above or in case the alkali is contained in one of the layers the fluid may merely be an aqueous solution supplied to release the alkali.

The silver halide emulsions of the sensitive elements of the invention include well known silver halides and mixtures thereof, for example, silver bromide, silver bromoiodide or silver chlorobromide emulsions. Negative emulsions are generally utilized, although good results can be obtained with direct positive emulsions, e.g., a reduction and gold sensitized emulsion of the type described in British Patent 723,019 (1955), an emulsion having a water-insoluble silver salt center and an outer shell composed of a fogged water-insoluble silver salt that develops to silver without exposure, as described in Berriman U.S. patent application Ser. No. 448,467 filed Apr. 15, 1965, now U.S. Patent 3,367,788 or the direct positive emulsions described in Illingsworth U.S. patent applications Ser. Nos. 609,794; 609,778 and 609,790; all filed Ian. 17, 1967 and which are now pending. When direct positive emulsions are utilized, there is obtained a negative dye transfer print composed of transferred dye developer, and a positive print composed of non-transferred dye developer when the silver image is bleached.

The elements described herein can be modified if desired for use in radiography, for example by utilizing an X-ray intensifying screen which can advantageously be coated integral with the light sensitive element, either above or below the emulsion and dye developer layers. Suitable integral X-ray intensifying layers can include a phosphor, such as barium lead sulfate or lead oxide dispersed in a suitable binder, such as an alkyl acrylateacrylic acid copolymer. The emulsion addenda described in the Whitmore et al. U.S. patent application Ser. No. 734,161, filed May 8, 1958, now U.S. Patent 2,948,102 and French Patent 1,205,755, Aug. 17, 1959, including the noble metal salts, stannous salts, polyamines, optical sen- 15 sitizing dyes, mercury compounds, quaternary ammonium salt and polyethylene glycol speed-increasing compounds, plasticizers, hardeners, coating aids and colloid vehicles disclosed therein may be used advantageously in the silver halide emulsion layers and adjacent layers of the sensitive elements of the present invention.

The use of photosensitive products containing the sulfur compounds of the invention is illustrated in the following examples. The processing compositions are in percent by volume.

Examples 1-2 A sensitive element is prepared by coating a subbed film support comprising cellulose acetate with suitably hardened gelatin layer as follows:

(1) Cyan developer layer.An aqueous gelatin solution containing the cyan dye developer l,4-bis[,8-(2,5'-dihydroxyphenyl)-propylamino]anthraquinone is dissolved in a mixture of N-n-butylacetanilide, 4-methyl cyclohexanone and dispersing agent Alkanol B. The mixture is passed through a colloid mill several times, coated and dried so as to volatilize the 4-methyl cyclohexanone. The mixture is coated onto the subbed support so as to yield a coverage of approximately 210 milligrams of the cyan dye developer per square foot and 250 milligrams of gelatin per square foot.

(2) Red-sensitive emulsion layer.A gelatino silver bromoiodide emulsion layer, which is sensitized to the red region of the spectrum is coated upon the cyan dye developer layer in amounts to provide 270 milligrams of silver per square foot and 200 milligrams of gelatin per square foot.

(3) Interlayer.A gelatin interlayer containing 4'- methylphenylhydroquinone is then coated so as to provide 250 milligrams of gelatin per square foot and 8 milligrams of 4'-methylphenylhydroquinone.

(4) Magenta dye developer layer.An aqueous gelatin solution containing the magenta 2[p-(2,5-dihydroxyphenethyD-phenylazo] 4 n propoxy-l-naphthol is dissolved in a mixture of cyclohexanone, N-n-butylacetanilide and Alkanol B is passed through a colloid mill several times, coated on the interlayer and dried to volatilize the cyclohexanone. This coating provides 77 milligrams of gelatin per square foot and 77 milligrams of the magenta dye developer per square foot.

(5) Green-sensitive emulsion layer.A green sensitive silver bromoiodide emulsion is coated on the magenta layer so as to yield a coverage of 108 milligrams of silver per square foot and 80 milligrams of gelatin.

(6) Interlayer.A second gelatin interlayer is coated onto the green sensitive emulsion at a coverage to provide 200 milligrams of gelatin per square foot and milligrams of 4-methylphenylhydroquinone.

(7) Yellow dye developer layer.An aqueous gelatin solution of the yellow dye developer, l-phenyl-3-N-nhexylca-rboxamido 4 [p (2',5 dihydroxyphenethyl)- phenylazo]-5-pyrazolone, is dissolved in a mixture of ditetrahydrofurfuryl adipate, ethyleneglycol monobenzyl ether, and Alkanol B, is passed through a colloid mill several times. The resulting dispersion is chilled to set it, Washed to remove ethylene glycol monobenzyl ether followed by coating upon the second interlayer and drying. The resulting coverage is 50 milligrams of gelatin per square foot and 50 milligrams of the yellow dye developer per square foot.

(8) Blue-sensitive emulsion layer.A blue sensitive silver bromoiodide emulsion is coated onto the yellow dye developer layer in amounts sufficient to provide 55 milligrams of silver per square foot and 41 milligrams of gelatin per square foot.

(9) Overcoat layer.A final gelatin emulsion overcoat layer is provided on the foregoing layers at a coverage of 40 milligrams of 4'-methylphenylhydroquinone and 100 milligrams of gelatin per square foot.

The gelatin layer containing the 4-methylphenylhydroquinone may be prepared in the manner described in US. Patent 3,146,102.

A sample of this freshly coated film is exposed under a step tablet through red, green and blue filters, and wetted with the processing compositions set forth in Table 1 while in contact with a receiving sheet comprising a white pigmented cellulose acetate support having a polyvinyl alcohol coating thereon containing po1y-4-vinyl pyridine mordant. The processing solution is spread at a roller gap of 0.004 inch (corresponding to the thickness of the activator layer). The cyan, magenta and yellow dye developer images are transferred from the undeveloped regions to the receiving sheets. After about 2 minutes at a temperature of 72 F., the receiving sheet containing the dye developer images is removed and density measurements of the dye images are recorded using red, green and blue filters in the usual manner.

TAB LE 1 Percent Example No 1 2 The processing solution of Example 2 yields considerably higher yellow and magenta maximum densities than that of Example 1, as shown in Table 5 below.

Examples 3-6 A sensitive element is prepared in the same manner as described in Examples 1 and 2, except that the concentration of the ingredients is varied as indicated below:

(1) Cyan dye developer layer.The cyan developer solution is coated onto the subbed support to yield a coverage of approximately 224 milligrams of the cyan per square foot and 250 milligrams of gelatin per square foot.

(2) Red-sensitive emulsion layer.A red sensitive gelatino silver bromoiodide emulsion layer is coated upon the cyan dye developer layers in amounts to provide a coverage of approximately 270 milligrams of silver per square foot and 200 milligrams of gelatin per square foot.

(3) Interlayer.A gelatin interlayer is provided at a coverage of 10 milligrams of 4'- methylphenylhydroquinone and 250 milligrams of gelatin per square foot.

(4) Magenta dye developer layer.An aqueous gelatin solution containing the magenta dye developed is coated on the interlayer so as to provide 84 milligrams of the magenta dye developer per square foot and 77 milligrams of gelatin per square foot coverage.

(5) Green-sensitive emulsion layer.A green-sensitive emulsion is coated on the magenta layer at a coverage of 108 milligrams of silver per square foot and 80 milligrams of gelatin per square foot.

(6) Interlayer.A coating of a second geltain interlayer is provided at a coverage of 10 milligrams per square foot 4'-methylphenylhydroquinone and 200 milligrams per square foot of gelatin.

(7) Yellow dye developer layer.An aqueous gelatin solution containing the yellow dye developer is coated onto the interlayer at a coverage of 50 milligrams of the yellow dye developer per square foot and 50 milligrams of gelatin per square foot.

(8) Blue-sensitive emulsion layer.A blue sensitive silver bromoiodide emulsion coated onto the yellow dye developer layer at a coverage of milligrams of silver per square foot and 82 milligrams of gelatin per square foot coverage.

(9) Overcoat.A gelatin overcoat is provided at a coverage of 49 milligrams of 4-methylphenylhydroqui- 17 none per square foot and 50 milligrams of gelatin per square foot.

A sample of this freshly coated film is exposed in the same manner as the previous examples, with the exception that a transfer time of only 1.5 minutes is employed. The composition of the processing solutions employed in Examples 8 are set forth below in Table 2.

The processing solution of Examples 4, 5 and 6 yields considerably higher yellow and magenta densities than that of Example 3, as shown in Table 5 below. Somewhat higher yellow and magenta densities are achieved with the processing composition of Example 6 when a 2 minute instead of a 1.5 minute transfer time is employed. The cyan density is greatly increased with the longer transfer time.

Examples 7-9 A photosensitive element is prepared in the manner of the previous examples except that the concentrations are varied in the following manner:

(1) Cyan dye developer layer.--A subbed cellulose acetate support is coated with the cyan dye developer in an amount sufficient to provide 120 milligrams per square foot of the developer and 141 milligrams per square foot gelatin.

(2) Red-sensitive emulsion layer.A red sensitized bromoiodide emulsion layer is coated onto the cyan dye developer layer at a coverage of 200 milligrams of silver per square foot and 155 milligrams of gelatin per square foot.

(3) Interlayen-A gelatin interlayer is coated onto the red sensitive silver halide layer in amounts suflicient to provide a concentration of 5 milligrams of 4'-methylphenylhydroquinone and 150 milligrams of gelatin per square foot.

(4) Magenta dye developer layer.The magenta dye developer is coated in an aqueous gelatin solution in amounts sufficient to provide 77 milligrams of the magenta dye developer per square foot and 77 milligrams of gelatin per square foot.

(5) Green-sensitive emulsion layer.The green sensitive silver halide emulsion layer is coated onto the magenta dye developer layer at the same concentration as the previous examples (6) Interlayer.A second gelatin interlayer is provided at a concentration of milligrams of 4'-methylphenylhydroquinone and 120 milligrams of gelatin per square foot coverage.

(7) Yellow dye developer layer.A yellow dye de veloper layer is coated on the second gelatin interlayer at the same concentration as the previous examples. A blue sensitive bromoiodide emulsion layer is coated onto the yellow dye developer layer so as to provide a coverage of 41 milligrams of gelatin per square foot and 55 milligrams of silver per square foot.

(8) Overcoat layer.A gelatin overcoat layer is provided at a coverage of 16 milligrams of 4'-methylphenylhydroquinone and 16 milligrams of gelatin per square foot.

A sample of the freshly coated film is exposed as in Examples 36 and wetted with the activator processing solutions set forth in Table 3. The receiving sheet employed in the following examples is a white pigmented cellulose acetate support having a gelatin coating which contains a poly-4-vinylpyridine mordant and l-phenyl-S- mercapto tetrazole.

TABLE 3 Percent Example No 7 8 9 High viscosity hydroxyethyl cellulose (Hercules t e 250 .5 3. 5 3. 5 5 4. 5 4. 5 0 2. 0 2. 0 1-benzyl-2-picolinium bromide 0. 5 0.5 0.5 4-hydroxypropyl-l-phenethylpyridinium bromide 1. 5 1. 5 1. 5 2,2 -thlodiethanol 4. 0 Dlmethylsulfoxide.

The overall improvement in the dye densities is shown in Table 5 below.

Examples 10-11 A fresh sample of the film is exposed in the usual manner and the receiving sheet of Examples 1-6 is employed with a transfer time of 1.5 minutes at a temperature of 73 F. The processing solution composition is specified in Table 4 below:

TABLE 4 Percent Example No 10 High viscosity hydroxyethyl cellulose HEO (Hercules type 250) Sodium hydroxide Benzotrlazole l-benzyl-2-picolim'um bromld Sodium thiosuliate Te tramethylarnmonium chloride. Dimethylsulfoxide PNPNNFF oooooocnou ple 11. The densities obtained are set out in Table 5 below.

TABLE 5 Example Dmnx miu Yellow Magenta Cyan Yellow Magenta Cyan 1 (control) 2. 26 1. 96 1. 96 l8 15 14 2. 50 2. 28 1. 96 21 18 16 1. 91 1. 50 1. 46 19 16 16 2. 16 1. 95 1. 46 21 18 18 2. 28 1. 90 1. 39 26 20 20 6 2. 34 2.08 1. 38 28 24 22 7 (control) 2. 62 2. 13 2. 42 19 14 16 8- 2.62 2.38 2.28 .20 .16 .15 9 3.00 2.61 2. 46 .21 15 15 10-- 2. 2. 36 l. 82 21 18 18 11 (control) 2. 66 2. 10 1. 21 18 18 The invention has been described in considerable detail with particular reference to preferred embodiments thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.

I claim:

1. A process for producing a photographic transfer image in color which comprises processing a photographic element comprising a plurality of light-sensitive silver halide emulsion layers sensitive to light of different regions of the spectrum, and a dye developer, which is both a silver halide developing agent and a dye, contiguous to the silver halide of said silver halide emulsion layers, said processing being effected by treating said photographic element with an alkaline solution, developing latent images in the regions of exposure of said silver halide layers and thereby immobilizing dye developers in said regions of exposure, dye developers in undeveloped regions dilfusing imagewise in register to a dye developer reception layer, and eifecting said processing in the presence of a sulfur-containing organic compound selected from the group consisting of dimethylsulfoxide, 2,2- thiodiethanol, and mixtures thereof.

2. The process of claim 1 wherein the sulfur-containing compound is dimethylsulfoxide.

3. The process of claim 1 wherein the sulfur-containing compound is provided in the alkaline solution.

4. The process of claim 3 wherein the sulfur-containing compound is employed in amounts in the range of between about 1 and about 15 percent by volume of the alkaline solution.

5. The process of claim 3 wherein the sulfur-containing compound is employed in amounts in the range of between about 1 and about 6 percent by volume of the alkaline solution.

6. The process of claim 3 wherein the alkaline solution additionally contains a heterocyclic quaternary ammonium compound capable of forming dilfusible methylene base in the alkaline solution.

7. The process of claim 3 wherein the alkaline solution additionally contains hydroxyethyl cellulose.

8. The process of claim wherein the sulfur-containing compound is dimethylsulfoxide.

9. A photographic product composed of a photosensitive element comprising a plurality of light-sensitive layers sensitive to light of different regions of the spectrum, and a dye developer which is both a silver halide developing agent and a dye contiguous to the silver halide of said silver halide emulsion layers, a dye developer reception layer, a rupturable container holding an aqueous alkaline processing solution, said photosensitive element and said dye developer reception layer being capable of being superposed on each other, and said container being so positioned as to be capable, upon being ruptured, of releasing said processing solution for application to said superposed photosensitive element and reception layer, and a sulfur-containing organic compound selected from the group consisting of dimethylsulfoxide, 2,2-thiodiethanol, and mixtures thereof so positioned in said product as to be present in said processing solution at the time of development.

.10. The photographic product of claim 9 wherein the sulfur-containing compound is dimethylsulfoxide.

11. The photographic product of claim 9 wherein the sulfur-containing organic compound is present in the rupturable container.

12. The photographic product of claim 9 wherein the sulfur-containing organic compound is provided in the dye developer reception layer.

References Cited UNITED STATES PATENTS 2,949,360 8/ 1960 Julian 96--100 XR 3,122,438 2/1964 Chalkley 96--9O 3,146,102 8/1964 Weyerts et a1. 96-29 NORMAN G. TORCHIN, Primary Examiner.

ALFONSO T. SURO PICO, Assistant Examiner.

U.S. C1. X.R. 

